Three people were killed and 20 were injured, including two 16-year-olds, in overnight gun violence. Two of those murders happened on the first day in May. One of them was a 27-year-old father of three.

"We're going to have good days, we're going to have bad days," Supt. Garry McCarthy told NBC 5. "The first four months of this year, we're in a position we haven't been in since the mid-'60s as far as the murder rate goes."

McCarthy pointed to 84 fewer murders in the past seven months and about 180 fewer shootings so far this year.

"We're moving in the right direction, but yes it is clearly not a good day," McCarthy said. "The fact is we have to examine what happened."

Among the shootings, a man in his 30s was found dead in an alley in the 1900 block of South Drake. After midnight, the first murder of May happened in the South Shore neighborhood where a 27-year-old man was shot in the chest near his home at 68th and Cornell.

Another shooting happened in front of the University of Illinois-Chicago police station, where three men were struck around 10:40 p.m. A 19- year-old who police said he was a known gang member died.

McCarthy said weather is a factor but not the cause of crime, noting "any city in this country" sees an increase in violence during summer months because more people are on the streets and kids are out of school.

McCarthy said the police department and Mayor Rahm Emanuel have a strategy and are constantly tweaking it to reduce crime and keep the trend line headed in the right direction.

"They might be statistics, but those are individuals," McCarthy said, "and that's what I really want to impart. We're not satisfied, not even close."